Man Utd 1-1 Arsenal
(Man Utd win 4-3 on pens)
Goalkeeper Tim Howard was Manchester United's hero as his double penalty save secured a Community Shield shoot-out win in Cardiff.
Howard saved from Giovanni Van Bronckhorst and Robert Pires to secure the season's first silverware - and erase his earlier error.
The American appeared at fault for Thierry Henry's 35-yard free-kick, which had cancelled out Mikael Silvestre's opener for United.
The result showed that title favourites United and Arsenal will be as hard as ever to separate when the new Premiership season begins.
And any questions over whether they were committed to what is effectively a pre-season friendly were answered within the opening 90 seconds.
Phil Neville was booked for a crunching tackle on Patrick Vieira with just 27 seconds on the clock.
SHOOT-OUT HITS AND MISSES
Paul Scholes scores
Rio Ferdinand scores
Howard save from Bronckhorst
Lehman save from Nistelrooy
Howard saves from Pires
A minute later, Arsenal's Ashley Cole followed him into referee Steve Bennett's notebook for upending Ole Gunnar Solskjaer.
And the competitiveness spilled over late on when Arsenal substitute Francis Jeffers was sent off for kicking out at Phil Neville.
There was still more than a little flair in the Community, with both sides keen to lay down their title credentials.
But it was Arsenal's defensive frailties that were once again highlighted by United's opener.
Arsene Wenger's brittle back line ultimately cost Arsenal the title last season - and a new look rearguard showed a familiar fragility.
Tim Howard celebrates his match-winning save
Kolo Toure, employed by Wenger as a makeshift centre-back alongside Sol Campbell, was handed an early lesson in the art of man-marking.
The Ivory Coast international left Silvestre completely unmarked from a Ryan Giggs corner and when Roy Keane flicked on the Frenchman could hardly fail with a free header.
The central defender, who delivered an outstanding performance, had started the move which led to his goal with a perfectly-weighted pass for Solskjaer to win the crucial corner.
He also tracked every run Thierry Henry made on a blisteringly hot afternoon at the Millennium Stadium.
But there was nothing Silvestre could do to prevent his French international team-mate from equalising on 20 minutes.
Nicky Butt was harshly adjudged to have fouled Vieira, and Henry greedily accepted the free-kick to fire home beyond the groping Howard.
Henry's finish blighted Howard's first competitive start for United.
He failed to line up his wall properly and then looking flat-footed when the kick was taken.
Yet glory ultimately belonged to the goalkeeper, though Arsenal substitute Pires and United's Eric Djemba-Djemba both went close in normal time.
Jeffers was dismissed for a petulant kick at Neville late on and Campbell was lucky not to follow when he kicked Djemba-Djemba as the game retained a competitive edge throughout.
But that was quickly forgotten - as was a rare missed penalty by Ruud Van Nistelrooy in the decisive shoot-out.
Manchester United: Howard, Phil Neville, Ferdinand, Keane, Silvestre,
Solskjaer, Butt, Fortune, Giggs, Scholes, van Nistelrooy. Subs:
Carroll, Bellion, Djemba-Djemba, Forlan, O'Shea, Richardson,
Arsenal: Lehmann, Lauren, Cole, Campbell, Toure, Parlour,
Ljungberg, Silva, Vieira, Henry, Bergkamp. Subs: Taylor, Pires,
Wiltord, van Bronckhorst, Edu, Cygan, Jeffers.
Referee: S Bennett (Kent)